You have to sneak in at Bandit Camp at night...
...Ok well I've done that, but now I've saved during the fight with Tank (which is incredibly easy) and am stuck fighting Scar... (which is insanely fucking difficult, but it wouldn't be if I had any chance at all to make some potions, which I didn't expect to need...) I do have a save several days before that that I suppose I could load, now that I *know* Scar needs like 10-15 health potions and 10-15 restrain potions to beat.
Supposedly this was made in Ren'Py, which AFAIK always has rollback, but maybe the dev turned off rollback somehow? It doesn't seem to work. (EDIT: Ok, looked it up and apparently it is possible to disable rollback in Ren'Py)